package cn.ly.design.action.agent;

/**
 * 理解不深刻
 * ？？
 * @author liuyu
 *
 */

public class Interpreter {
	public static void main(String[] args) {
		// 计算9+2-8的值
		int result = new Minus().interpret((new Context(new Plus().interpret(new Context(9, 2)), 8)));
		System.out.println(result);
	}
}

interface Expression {
	public int interpret(Context context);
}

class Plus implements Expression {

	@Override
	public int interpret(Context context) {
		return context.getNum1() + context.getNum2();
	}
}

class Minus implements Expression {

	@Override
	public int interpret(Context context) {
		return context.getNum1() - context.getNum2();
	}
}

class Context {

	private int num1;
	private int num2;

	public Context(int num1, int num2) {
		this.num1 = num1;
		this.num2 = num2;
	}

	public int getNum1() {
		return num1;
	}

	public void setNum1(int num1) {
		this.num1 = num1;
	}

	public int getNum2() {
		return num2;
	}

	public void setNum2(int num2) {
		this.num2 = num2;
	}

}
